Wheel bearings are manufactured in a variety of different sizes. However, different sizes of wheel bearings can often have very similar dimensions. The similarity between different size wheel bearings can result in the use of the wrong type of wheel bearing in a wheel assembly. This problem is of particular importance in the airline industry. Different models of aircraft usually require different types of wheel bearings in their wheel assemblies. Typically, there are many different types of wheel bearings to choose from in selecting the correct type for a particular model of aircraft. In most aircraft, there are two wheel bearings in each wheel assembly, one called the inboard bearing (IB) and the other the outboard bearing (OB). Not only does bearing size vary among aircraft models, but each wheel bearing in the pair within a wheel assembly is generally a different size.
There can be five variables that distinguish the different types of wheel bearings. The five variables are the (1) outside diameter of the wheel bearing, (2) the inside diameter of the wheel bearing, (3) the number of rollers, (4) the taper angle of the outer circumference of the bearing, and (5) the height of the bearing. Generally, at least four of these five potential variables are required to be known to distinguish one bearing from another. Of the different types of bearings, several are so close in size that the differences in their dimensions are not easily discernible with the human eye. Although many of the bearings are very close in size, it is essential that a mechanic use a bearing of the correct size in the wheel assembly. Using a bearing that is only slightly different from the correct size bearing can cause a failure in the bearing due to the significant stress in the wheel assembly during take-off and landing of aircraft.
Each of the different types of bearings are stamped with a serial number that identifies the bearing. In the conventional approach to selecting the correct bearing, the mechanic checks the serial number on each bearing before installing it in the wheel assembly. The problem with this approach is that humans occasionally make errors and could inaccurately read the serial number stamped on the bearing. This potential for inaccuracy is compounded by the fact that the serial numbers used on typical aircraft wheel bearings are generally several digits long and use many of the same digits. One attempt at solving this problem was the use of a “go-no go” gauge. The “go-no go” gauge was simply a piece of material cut to the size of the inside diameter of a particular wheel bearing. When selecting a wheel bearing, a mechanic would slide the wheel bearing onto the “go-no go” gauge to insure that it was the correct size. However, the “go-no go” gauge is limited in that it only measures one of the five potential variables that distinguish wheel bearings. For example, a mechanic could use a wheel bearing with the correct inside diameter, according to the “go-no go” gauge, but an incorrect outside diameter.
In view of the foregoing, there is a need in the art for an apparatus that can accurately differentiate various sizes of wheel bearings. There is a further need for an apparatus that protects a wheel bearing from damage or contamination while it is stored until subsequent use in a wheel assembly. There is also a need for a method for efficiently employing the apparatus in a machine shop environment where wheel assemblies are taken apart and reconstructed. The present invention can facilitate selection of the correct size of wheel bearing for insertion in the wheel assembly of an aircraft.